Multiple forms of an angiogenesis factor: basic fibroblast growth factor

Abstract

An angiogenesis factor has been isolated from human placenta and human hepatoma cells on the basic of its ability to stimulate protease production in cultured capillary endothelial cells. The purified angiogenesis factor also stimulated DNA synthesis and motility in capillary endothelial cells and induced angiogenesis in vivo. Amino acid sequence data revealed that the angiogenesis factor was human basic fibroblast growth factor (bFGF). Other angiogenesis factors isolated on the basis of their ability to stimulate endothelial cell proliferation have also been identified as bFGFs. The bFGFs that have been sequenced show variability in their N-termini. These different forms of bFGF may be naturally occurring processed forms or may be generated by proteases released during the isolation procedure. Recently a bFGF with a large N-terminal extension has been identified. This M r 25 000 bFGF has the same biological activity and the same affinity for the bFGF receptor as the typical M r 18 000 bFGFs. The M r 25 000 bFGF can be converted into an M r 18 000 form by treatment with low concentrations of trypsin, suggesting that it may be a precursor to the M r 18 000 bFGF.